Study On Determining Reasonable Cable Force Of Shortpylon Cable-stayed Bridge And Analyzing The Effect Of Cable Force To Structure

The cable force is the key parameter of short-pylon cable-stayed bridge.A small change in cable forces can lead to a large change in structural line-type and internal forces.The changes in cable forces during construction and due to damage in service can cause changes of the cable force.In this paper,taking Chibilu bridge in Lu’an city,Anhui Province,as an example,the studies are focused on the cable force to determine the reasonable cable forces during construction,cable force measurements and effect of cable force change on the structural behavior in service.The results of this paper can provide the reference to the design and construction for the same type of bridges.In this paper,the main research work and conclusions includes:(1)The construction process of Chibilu bridge is introduced in detail and the finite element model is established.The static and dynamic in completed bridge state are carried out accordingly.The results indicate that Chibilu bridge has reasonable loading behavior that meets the requirement of the design.(2)Combining with Newton iteration method and existing forward iteration methods, this paper proposes a method to determine the reasonable cable forces during construction.The method is based on the forward iteration method and influence matrix.It is demonstrated that the proposed forward iteration method form only one matrix and also has a good convergence.(3)Several kinds of cable force test methods are described.The related theory of vibration-based cable tension method is introduced in detail.The results came from different formulas show that the effect of cable flexural rigidity and boundary conditions must be considered for the short-pylon cable-stayed bridge when determining reasonable cable force of Chibilu bridge.(4)By using established finite element model,the effects of cable force errors during bridge construction on the girder line-type,girder internal force,pylon deformation and final cable forces are investigated.Also,both structural and dynamic behavior after the breakages of cables in different positions is studied.The outcomes can be used to the safe service evaluation and health monitoring of Chibilu bridge.